Here we have a mortice sashlock that has gone faulty, the key mechanism has a fault and it can often take 10 minutes to lock or unlock the door. This is serious and needs urgent attention! If there was a fire in the property and you were fumbling with the lock it could cost you your life, or at the very least it could refuse to open at all and you could be landed with a large locksmith's bill!


Sashlock's come in two sizes 64mm (2.1/2in) from the face plate to the back of the lock, or 76mm (3in) from the face plate to the back of the lock.

Different manufactures produce slightly different sized locks and so it is important to get a similar lock or else lots more work could be involved.

The difference between a deadlock and a sashlock is that the latter includes a latch as well as a lock. The latch is operated by door handles or door knobs.


Mortice sashlock

This is the replacement mortice sashlock that I have purchased to replace the faulty one. When purchasing a new lock it is important to get the correct size of lock. If possible get an identical make as the one you are replacing as this will be close to the exact size of lock that you need.

This is going on a front door of a property and so is an insurance approved 5 lever lock.

Mortice sashlock

This is the view of the sashlock from inside of the property.

remove door handle

Unlock the door and open it, then jam a piece of wood between the door so that it cannot accidentally close. Unscrew the screws on the door handle, you only need to do this on one side of the door.

remove spindle

Remove the Handle from the door and then remove the spindle. ( the spindle is a square metal bar that fits through the lock and each handle )

remove sashlock

Now remove the screws that are holding the lock into the door and remove the lock from the door

enlarge hole

Often the new lock will be slightly bigger or smaller than the existing lock. This could be due to the age of the lock as they tend to last a very long time. If the lock is too big then you will have to removes some wood from the aperture using a sharp wood chisel and mallet.

refit lock

You must ensure that the latch is pointing the correct way before fitting it. This can be turned around by undoing one or two screws. The lock should fit flush with the surface of the door and can now be screwed back in place.

insert spindle

Push the spindle through the lock and into the other door handle and then refit the internal door handle. Check that the lock functions correctly.

Mortice sashlock

Once installed you will never know it's been replaced